fix: Process header cells as any other cell (#244)

lib/JSON2CSVBase.js

@@ -49,10 +49,8 @@ class JSON2CSVBase {
         (typeof field === 'string')
           ? field
           : (field.label || field.value)
-      ).map(header =>
-        JSON.stringify(header)
-          .replace(/"/g, this.params.quote)
       )
+      .map(header => this.processValue(header, true))
       .join(this.params.delimiter);
   }
 
@@ -86,7 +84,7 @@ class JSON2CSVBase {
     }
 
     return this.params.fields
-      .map(fieldInfo => this.processField(row, fieldInfo))
+      .map(fieldInfo => this.processCell(row, fieldInfo))
       .join(this.params.delimiter);
   }
 
@@ -97,14 +95,25 @@ class JSON2CSVBase {
    * @param {Object} fieldInfo Details of the field to process to be a CSV cell
    * @returns {String} CSV string (cell)
    */
-  processField(row, fieldInfo) {
-    const isFieldInfoObject = typeof fieldInfo === 'object';
-    const defaultValue = isFieldInfoObject && 'default' in fieldInfo
-      ? fieldInfo.default
-      : this.params.defaultValue;
-    const stringify = isFieldInfoObject && fieldInfo.stringify !== undefined
+  processCell(row, fieldInfo) {
+    const stringify = typeof fieldInfo === 'object' && fieldInfo.stringify !== undefined
       ? fieldInfo.stringify
       : true;
+
+    return this.processValue(this.getValue(row, fieldInfo), stringify);
+  }
+
+  /**
+   * Create the content of a specfic CSV row cell
+   *
+   * @param {Object} row JSON object representing the  CSV row that the cell belongs to
+   * @param {Object} fieldInfo Details of the field to process to be a CSV cell
+   * @returns {Any} Field value
+   */
+  getValue(row, fieldInfo) {
+    const defaultValue = typeof fieldInfo === 'object' && 'default' in fieldInfo
+      ? fieldInfo.default
+      : this.params.defaultValue;
 
     let value;
     if (fieldInfo) {
@@ -123,10 +132,19 @@ class JSON2CSVBase {
       }
     }
 
-    value = (value === null || value === undefined)
+    return (value === null || value === undefined)
       ? defaultValue
       : value;
+  }
 
+  /**
+   * Create the content of a specfic CSV row cell
+   *
+   * @param {Any} value Value to be included in a CSV cell
+   * @param {Boolean} stringify Details of the field to process to be a CSV cell
+   * @returns {String} Value stringified and processed
+   */
+  processValue(value, stringify) {
     if (value === null || value === undefined) {
       return undefined;
     }

test/fixtures/csv/excelStrings.csv

@@ -1,4 +1,4 @@
-"carModel","price","color"
+"=""carModel""","=""price""","=""color"""
 "=""Audi""",0,"=""blue"""
 "=""BMW""",15000,"=""red"""
 "=""Mercedes""",20000,"=""yellow"""